Lull 944E-42 Service Manual User Manual
Page 483
8.231
Model 644E-42/944E-42
Rev. 6/04
Hydraulic System
IMPORTANT: Protect the finish on the rod at all times.
Damage to the rod can cause premature seal failure.
4. Use a pin spanner wrench to unthread the head
gland (4) from the tube (5). The head gland is
installed at a torque of 300-400 lb-ft (407-542 Nm),
so a considerable amount of force is required to
remove it. Carefully slide the head gland down along
the rod toward the eyelet end, away from the cylinder
tube.
5. Remove the locking insert (6) from its hole in the
head gland threads. Pry or drill out the insert as
required. DO NOT damage the head gland threads.
A new locking insert will be required for reassembly.
IMPORTANT: When sliding the rod and piston assembly
in the tube, DO NOT damage the piston by scraping it
against the threads in the tube. Keep the rod in line with
the tube to prevent binding.
6. Carefully withdraw the rod (7) straight out of the
tube (5). Keep the rod straight during withdrawal to
help avoid scratching, nicking or damaging the
tube (5).
7. Secure the rod eyelet and remove the locknut (8)
from the threaded end of the rod. Discard the nut; a
new nut will be required for reassembly.
Note: Heating the nut (8) to approximately 300° F
(150° C) may also be required to break the seal formed
by the Loctite Threadlocker #271 (red) applied to the nut
when installed. The application of significant force is
required to overcome the 1840-2025 lb-ft
(2495-2745 Nm) of torque to the nut.
8. Remove the piston (9) from the rod (7).
9. Remove the small o-ring (10) from the piston.
10. Remove the head gland (4) from the rod (7).
11. Remove both precision wearbands (11) from the
piston (9).
12. Remove the capped T-seal (12) from the piston (9).
Note: The T-seal actually consists of four components; a
wide, flexible inner band, the flexible T-seal band itself,
and two supportive split caps that mount on either side of
the “T” seal band.
13. Remove the o-ring (13), the back-up ring (14) and
the o-ring (15) from the head gland (4).
14. Remove the heavy-duty rod wiper (16) from the head
gland (4).
15. Remove the precision wearband (17) and deep
Z-seal with rod back-up (18) from inside the head
gland (4).
16. Inspect and remove the two polylube bearings (19).
17. Remove the two plugs (20) from the base end of the
tube.
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